From Swiss Patent No. 394,071 (corresponds to U.S. Pat. No. 3,285,291), a dobby of the Hattersley system has become known, in which the movement of the baulks which finitely control the end position of the heddles, is carried out by bars which act with a pushing force onto the ends of the baulk. This pushing force takes place constantly in the same rhythm. To control the position of the baulk, and with it also of the attached heddle, cooperating draw and arrester or holding hooks are used. The latter are controlled from a pattern card such that the draw hooks engage or do not engage, depending on the patternlike upper shed or lower shed position of the heddle.
However, a dobby is also known, in which in order to shorten the control time, or rather to increase the operating rhythm, certain control functions, in particular reading of a pattern card and transmitting of the read information is advanced or stored into the actual operating time.
All such inventions have the object of increasing the operating speed and the economics of the dobbies.
The result of such a development for a dobby according to Swiss Pat. No. 394,071 is described more in detail in Swiss Pat. No. 472,517 (corresponds to U.S. Pat. No. 3,441,060). Here a holding hook is shown, which permits an anticipatory control. This holding hook consists of two two-arm levers, which are supported on shafts and can be swung against one another against the force of springs. High speeds can be achieved therewith.
The purpose of the invention is to find a simple solution for reducing the manufacturing and installation expenses and to achieve a greater work output.
This is achieved inventively in a negative double-lift dobby of the above-mentioned type by the holding hooks being able to be controlled by a pattern card and being able to be moved into the range of movement of the draw hooks and a deflecting spring being arranged on the draw or holding hooks, which deflecting spring permits a yielding of the holding hooks with respect to the connecting position.